By Cindy Carroll, RD, RN, IFNCP
33 %, 55 %, 72 %, 88 % These percentages could represent nearly anything in life—but for those of you who have any affection for chocolate, you might recognize them as the percentage of cacao by weight listed on chocolate containing foods. Chocolate research has exploded in the last decade and the food industry is jumping on board, wanting to show that their products have some amount of this esteemed ingredient, cacao, pronounced "ca-cow". I thought I knew a little something about chocolate but as with so many topics in nutrition, once you dive in and investigate there is always so much more. The chocolate industry and science is complicated….losts of rules and variables. Before we get to the heart of chocolate’s benefits, let’s look at some basics.
Cacao beans are the fermented seeds from the dried cocao plant. Cacao powder is the solids of cocao beans minus the natural fats (cocoa butter). Chocolate is catagorized by the content of cacao by weight in the forms of liquor, powder and cacao butter. Dark is referred to as semisweet and extra dark as bittersweet, although the ratio of cocoa butter to solids may vary, usually ranging from 70-99 % cacao solids. White chocolate actually contains no cacao solids, just milk, cocoa butter and sugar. Milk chocolate must contain a certain percentage of milk. The greater the cacao solids, generally the less sugar and more bitter taste. Which products may be labeled "dark chocolate" and “milk chocolate” vary by country and government and industry standards.
Chocolate and I go way back—probably to the womb because my mom loved chocolate too. She lived to be 94—didn’t let a day go by without eating something chocolate—peppermint patties, chocolate bars, chocolate ice cream. She really loved just straight chocolate and I can remember my Dad indulging her now and again with a “surprise” large Hershey chocolate bar and hiding it in the refrigerator for her to find. So, of course growing up with all of that chocolate in the air, it was only natural for me to partake. Chocolate ice cream was my favorite indulgent. Back then I didn’t worry too much about calories—life was good, just me and my bowl of premium Hood ice cream watching the Wizard of Oz.
So, it’s always good when life-long patterns of anything end up actually having some redeeming qualities. Research is showing that all of the cocoa beans I’ve consumed over the years may be quite beneficial but as in anything in life, they also come with a few risks. Let’s get the risks out of the way and save the best for last.
The combination of chocolate and sugar together is a no brainer for manufacturers….it is in part, what keeps us going back for more. Also, depending on the percent cacao, there may be higher sugar in the chocolate itself. Read the label to see how many grams of total sugar are in the product. Generally, the more cacao solids and cacao fat, the less sugar, however a manufacturer can add any amount of sugar or sweetener into the mix. On a positive note, I’ve seen many clients better manage their “sweet tooth” by enjoying the bitter taste of dark chocolate. For some with sensitive GIs, cocoa may be irritating and the more milk in the chocolate, the greater the lactose and potential fodmap content. According to Monash university, a 30 gram portion of dark chocolate is considered low fodmap, which is about 2 tablespoons of semi sweet morsels, 1 heaping tablespoon of cacao powder or 5 small squares.
Cadmium is an unwanted heavy metal found in cacao. It is also a carcinogen, can weaken bones and be toxic to the liver. Smoking and high risk occupations are the greatest risk for inhaling cadmium but otherwise, food is our greatest source for non-smokers. Strict vegans have higher cadmium blood levels than non-vegans. Certified organic plants/foods does not eliminate or reduce cadium risk. But don’t panic, although, minimizing total exposure of cadium is of course better, it is the absorption of any heavy metal that is important. Many factors affect absorption including other heavy metals in the diet such as calcium, magnesium and iron, which compete with cadmium and may help decrease its absorption. Also, cadmium in plants contain fiber and phytates, which may also interfere with cadium’s absorption. Research shows people who are vegetarian, although may have a greater cadmium intake may also have decreased absorption because of the antioxidants and phytates in those same plants. Overall, nutritional status is a more important determinant of cadmium uptake into the body than is the actual amount of cadmium ingested.
For the Good of Chocolate
Back in the day—in my early chocolate years, I didn’t have a clue about polyphenols or flavanols. I just loved the flavor and feel of chocolate in my mouth. From a nutrition perspective, dark chocholate is relatively low in sugar, high in fiber—but the true benefits probably lie in the polyphenols. Polyphenols are a large class of phytonutrients that research has been studying for decades. Flavonoids are a large subgroup of polyphenols. Flavonoids include flavanols, flavonols and proanthocyanins--(who made these up?) There are thought to be over 6,000 flavonoids in plants. Other foods high in flavonoids include berries, teas, and wine.
Gut Microbiome and Flavanols- Prebiotic Effect
The numerous health benefits associated with flavanols in cocoa may be attributed to their prebiotic effect on our gut bacteria, thereby affecting the growth of certain gut organisms. Research shows that polyphenols in foods have a "give and take" effect on our gut microbiome. Almost like they know they are living together in tight quarters —“Hey, you help me out and I’ll help you”. The microbes convert polyphenols into their beneficial metabolites or byproducts, and in turn the polyphenols influence the composition of the gut bugs, probably by inhibiiting more troublesome bacteria and stimulating beneficial bacteria. One of the first studies to demonstrate this with cacao, compared the consumption of a low cocoa drink, to a high cocoa drink. In a four week period, the high cocoa drink significantly increased the bifidobacteria and lactobacillus bacteria, while also significantly decreasing clostridia counts. Other positive changes included significant reductions in plasma triglycerides and C-reactive protein.
The benefits of chocolate are thought to stem primarily from the cocoa flavanols, especially the epicatechins but other compounds in chocolate such as caffeine and threobromine also have effects and need more research. Some of the research is conflicting but the studies are growing in number. Here is a glimmer into some of the benefits from flavanols.
Decreased blood pressure and lipids are among the potential cardiovascular benefits seen in populations who consume chocolate. The Flaviola Health Study applied the Framingham heart study risk scores to healhy people without CVS and showed that flavanol intake improved blood vessel function, lipids and blood pressure. The study predicted a significant lowering of 10-year risk for CHD. Similar findings have been found in studies with people with CVD risk. https://www.ncbi.nlm.nih.gov/pubmed/26348767 https://www.nature.com/ejcn/journal/v71/n9/pdf/ejcn201736a.pdf
Eight clinical trials have demonstrated daily cocoa flavanol intake between 200-600 mg/day significantly decreased fasting blood glucose, fasting insulin and HOMA-IR in people with CVD risk factors. There is some suggestion that higher intakes- more than 600 mg/day may raise blood glucose, possibly because of an association with threobromine in cocoa. Threobromine when given 500 mg/day has been associated with elevated blood glucose. I would not avoid dark chocolate for fear of it elevating your blood sugar, unless you are consuming high sugar choices and large, daily amounts. Also, we know based on other gut microbiota research that each person’s gut flora is unique in determinig their response to carbohydrates and food in the diet.
Atrial fibrilliation (a fib) is one of the most common heart arrthymias and has the potential for serious consequences such as stroke. A 13.5 year study in Denmark showed the risk of a fib decreased significantly in proportion to the chocolate consumed, with 2-6 servings per week giving the greatest, 20 % reduction of atrial fibrilliation.
A small study showed that people with peripheral vascular disease were able to walk 15% further than normal when they consumed 40 grams of dark chocolate, greater 85 % cacoa within two hours of exercise . https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4310398/
Research suggests that flavanols are able to cross the blood brain barrior and reach brain cells. https://www.ncbi.nlm.nih.gov/pubmed/26047963 In a 2-month, double blind study (CoCoA study) with 90 elderly people without cognitive problems, those who drank the high flavanol had the greatest improvement in specific cognition markers, particularly processing speed but also improvements in insulin resistance and blood pressure.
Clincal studies suggest the following intakes of flavanols for health purposes
- Cardiovascular health: 200-900 mg/day
- Blood sugar/insulin improvement 200-600- mg/day
- Memory/cognitive function 500-900 mg/day
- Skin elsasticity/wrinkles 320 mg/day
Food products differ but here is a rough estimate of chocolate serving size needed to meet 200 mg flavanols.
Cocoa powders generally contain more cadium per weight than solid chocolate. Aim to eat the lowest cadium per weight of flavanols. Endangered Species and Baker’s unsweetened chocolate bar had of the lowest cadium for high flavanol ratio and Trader Joes Dark chocolate Lover’s Bar 85% had a high cadmium for flavanols ratio. For more information, see Consumerlab’s latest reveiw on chocolate. https://www.consumerlab.com/reviews/Cocoa_Powders_and_Chocolates_Sources_of_Flavanols/cocoa-flavanols/
Here’s to epicatechins or flavanol concentration on future food labels---or TMI? Flavanols, splavanols.....I'm still eating my chocolate.